1. Field of the Invention
The present invention generally relates to a mobile communication terminal. More particularly, the present invention relates to a method for fabricating an antenna device of a mobile communication terminal.
2. Description of the Related Art
Generally, the term ‘mobile communication terminal’ refers to a device carried with a user to perform communication, such as voice communication or text message transmission/reception, between the user and a communication partner. Recent years have witnessed innovative advances in mobile communication technology such that a user can download various contents provided from a mobile communication service provider through the mobile communication terminal and store the contents in the mobile communication terminal for use on the mobile communication terminal or enjoy those contents online.
Mobile communication services, which provided simple voice communication or text message transmission/reception in their early stage, are now additionally enabling the real-time transmission/reception of large amounts of information, from transmission/reception of various game contents and still/moving pictures to video communication.
Mobile communication services are provided in allocated frequency bands which may differ geographically and/or from service provider to service provider. Recently, mobile communication services provided in different frequency bands have become available with a single mobile communication terminal.
Meanwhile, as mobile communication services, which were focused on voice communication or short message transmission in their early stage, are now diversified from the transmission of game contents and still/moving pictures to video communication, terminal manufacturers have made continuous efforts to provide increasingly smaller terminals having large screens. That is, mobile communication terminals need to be easy to carry and allow users to enjoy multimedia services with sufficiently large screens during video communication or the viewing of moving pictures. In terms of portability and convenience in use of multimedia services, a portable terminal having a touch screen capable of providing both a keypad function as an input device and a display function as an output device has rapidly come into wide use.
To use mobile communication services provided in different frequency bands through a single mobile communication terminal, the mobile communication terminal has to be equipped with antennas operating in the respective frequency bands. However, due to the nature of antennas, interference generated between antennas operating in different frequency bands may lead to many difficulties in installing a plurality of antennas in a downsized terminal. Moreover, with the recent trend toward a built-in antenna which is disposed in a housing of a terminal, such difficulties have been aggravated.
Furthermore, because the characteristics of antennas may be significantly influenced by an adjacent circuit device or the shape of a terminal's housing, as well as interference between antennas operating in different frequency bands, an antenna for a new model of a terminal is designed through a trial and error process that inevitably involves numerous trials. In other words, for a new model of a terminal, a user can intuitively recognize only exterior and functional changes in the terminal. However, to design an antenna device for the new model of the terminal so as to have sufficient performance, a circuit layout and shape of a housing of the terminal as well as the design of the antenna device go through many trials and errors.
The trials and errors involved in the antenna design process require many man hours and are expensive, thereby increasing the fabricating cost of the terminal.
In addition, an antenna generally needs an electrical length of either a ¼ wavelength or ½ wavelength of a resonance frequency. An antenna operating in a high-frequency band (e.g., a band around 1.8 GHz or 2.1 GHz) is relatively easy to downsize. On the other hand, an antenna operating in a low-frequency band (e.g., a band around 800 MHz) needs a larger physical installation space than the antenna operating in the high-frequency band.
Therefore, in the design of a multi-frequency-band antenna, there exist many difficulties in securing an installation space and guaranteeing the independent operating characteristics of the antenna operating in the low-frequency band with respect to the antenna operating in the high-frequency band.